1. Field of the Invention
The present invention relates to a mechanism for operating a nozzle assembly of variable geometry turbocharger, and more particularly, to a mechanism adjusting rotational angle of vanes to control flow of an exhaust gas flowing through nozzles.
2. Description of Related Art
Variable geometry turbochargers of the related art have an exhaust pipe on the center axis of a turbine in a turbine housing such that the exhaust gas discharged from an internal combustion engine flows from the outside to the inside of the turbine and is exhausted from the turbochargers through the exhaust pipe, and the flow of the exhaust gas flowing into the turbine from the outside of the turbine is controlled by a nozzle assembly disposed outside the turbine.
The nozzle assembly of the related art includes a nozzle ring where a plurality of vanes are rotatably mounted in a circle; a nozzle plate disposed apart from the nozzle ring, with the vanes therebetween, to form a nozzle through which an exhaust gas passes; a control ring arranged coaxially with the nozzle ring to be able to rotate with respect to the nozzle ring and receive operation force for adjusting rotational angle of the vanes from the outside; and a plurality of operation links connecting the control ring with the rotational shafts of the vanes such that the vanes rotate, when the control ring rotates with respect to the nozzle ring.
The control ring has a plurality of connection portions where the ends of the operation links are fitted to transmit the relative rotation of the control ring to the nozzle ring as rotation force for the vanes. The connecting portion is a simple groove or hole, such that it causes significant friction and wear against the operational links, thereby decreasing durability.
Further, the connection structure between the connecting portions and the operation link is relatively complicated, such that machineability is bad. Further, the gaps between the parts are set relatively large in consideration of high-temperature thermal expansion, such that silence and stability are decreased and vibration may be generated in the operation.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.